1. Field of the Invention
The present invention relates to an input device, and more particularly to a touch input device.
2. Description of the Prior Art
Many existing electronic equipment, such as a hand-held electronic device and a computer including a cell phone, a personal digital assistant (PDA) and a Global Positioning System (GPS) navigator, will usually require an input device like a keyboard, a mouse or a touch panel, to operate. As the touch panel can be integrated with a screen of the electronic equipment to form a touch screen, the touch panel is used widely.
FIG. 1A shows a top view of a conventional touch panel and FIG. 1B is a cutaway view along the line I-I of FIG. 1A. As shown in the drawings, the conventional touch panel 100 includes a transparent glass plate 110, plural vertical conductive strips 120, plural horizontal conductive strips 130 and a chip 140.
The transparent glass plate 110 is provided with an upper surface 112 and a lower surface 114 which is opposite to the upper surface 112. The vertical conductive strips 120 are all configured on the upper surface 112, and the horizontal conductive strips 130 are all configured on the lower surface 114. In other words, the vertical conductive strips 120 and the horizontal conductive strips 130 are configured respectively on the two opposite surfaces of the transparent glass plate 110.
Accordingly, the vertical conductive strips 120 and the horizontal conductive strips 130 are all transparent indium-tin oxide (ITO) films, and are provided respectively with plural conductive layers 122, 132, wherein the conductive layers 122 in any one vertical conductive strip 120 are electrically connected with one another, and the conductive layers 132 in any one horizontal conductive strip 130 are electrically connected with one another.
The chip 140 is provided with plural input-output contacts 142 which are one-to-one electrically connected to the vertical conductive strips 120 and the horizontal conductive strips 130. Therefore, a total number of the vertical conductive strips 120 and the horizontal conductive strips 130 will be equal to a number of the input-output contacts 142, and the chip 140 is electrically connected to the vertical conductive strips 120 and the horizontal conductive strips 130.
When a touch pen P1 contacts the upper surface 112 or the conductive layers 122, a capacitance value of the vertical conductive strip 120 or the horizontal conductive strip 130 that corresponds to the touch pen P1 will be changed. At this time, the chip 140 will be aware of a position of the touch pen P1 according to the changed capacitance value, so as to move a cursor which is displayed on the screen of the electronic equipment, allowing a user to operate the electronic equipment such as the hand-held electronic device or the computer from the touch panel 100.
Accordingly, each vertical conductive strip 120 and each horizontal conductive strip 130 can serve as a sensor to detect the position of the touch pen P1, respectively. Hence, a number of the sensors that the touch panel 100 is provided with are equal to the total number of the vertical conductive strips 120 and the horizontal conductive strips 130. Taking FIG. 1A as an example, the touch panel 100 includes 5 vertical conductive strips 120 and 4 horizontal conductive strips 130; thus, there are 9 sensors in the touch panel 100.
In general, the more sensors the touch panel 100 has, the higher the accuracy of the touch panel 100 will be provided with; that is, the touch panel 100 can more accurately detect the position of the touch pen P1, so as to accurately control the movement of the cursor. In order to improve the accuracy of the touch panel 100, many companies, factories, enterprises and academic institutes nowadays are developing toward increasing the numbers of the vertical conductive strips 120 and the horizontal conductive strips 130, in the research of the touch panel 100.